portrait of a platoon in an
American division in the mountains of Korea and their trial by fire

Spoiler Warning: below is a summary of the
entire film.

A jeep comes racing down the snow-covered road until it is hit by Chinese artillery.
The jeep was carrying the general. He is now in the C.P. getting patched up.
The general receives a call telling him that the whole division is withdrawing.
They have to cross a river and there is only one bridge providing an exit for
the troops. The Chinese communists have two divisions and elements of a
regiment behind a hill. If they learn that the whole unit is withdrawing,
they might launch an immediate attack. To prevent the enemy from
finding out about the withdrawal, the general decides to use a rearguard action. The rearguard
will have to give the enemy the impression that the rearguard is a forward
outpost to the division's bivouac.

The only pass through the mountains in the area is Bayonet Pass. If
they station the rearguard at a critical bend in the pass, they may be able to
fool the Chinese. The general decides to use a platoon of forty-eight of
their toughest, most experienced combat men. He tells Col. Taylor to pick
a platoon out of his regiment to use as the rearguard. The selected platoon will
hold the line so that 15,000 men are given a "break".

The unit starts leaving. The chosen platoon watches them move out.
The men of the platoon don't look happy about their assignment. After the
division is out of sight, the men start preparing their defensive positions.
Some of the men ask Sgt. Rock what is a rearguard? The erudite Corporal Denno says: "The object of the rearguard is to check enemy pursuit and
harassment and thus allow the main body to retire unmolested." A few
of the guys don't even understand what Denno told them.

The men get into their positions ready for any action. A Chinese
soldier starts walking up the pass. Denno sees him, but has a mental block
that prevents him from shooting the man. The soldier gets closer and
closer, until another soldier, Jonesy, shoots the enemy soldier dead. Sgt.
Rock
congratulates Denno on his shot and says he is now a real rifleman --
he's been baptized. Denno says nothing.

Wolowicz plants anti-tank and anti-personnel mines around the area. The
lieutenant tells Wolowicz to make a map of where the mines are and make sure he
gets it. The Chinese start blowing their bugles and the American soldiers prepare for an
assault. But no assault comes. Sgt. Rock asks Denno what happened at
officer candidates' school? Denno replies: "I just figured out I was
never cut out to be a leader of anything." Rock tells him that he is just
three men away from commanding this platoon: Lt. Gibbs, Sgt. Lonergan and
Rock himself. This upsets Denno who denies the possibility that the tough
Rock can be killed.

Just then a Chinese mortar position opens up on the men. Sgt. Rock
telephones an order for a mortar response and gives the range. He keeps
calling in more precise directions until the mortar hits its target. The
lieutenant tells everyone to take a break, but just then Chinese artillery opens
up on them. They pulverize Rock and Denno's position. The men have to
get the hell out of there in order to survive. One soldier is wounded by
shrapnel. The only good thing about the assault is that Sgt. Rock found a
cave in the side of the mountain.

Rock knocks icicles down from the cave roof, until he hits a solid stalactite
and the gun is knocked from his hands. A little later Rock trips over a
stalagmite and falls into a pool of icy water right in the middle of the cave
entrance area. At the end of the pond is a huge chasm. Mr.
Know-it-All Whitey warns the sergeant of the possibility of deadly ricochets
inside the cave. The walls will tear up the bullets and make them very
jagged so that the bullets becomes exceptionally lethal.

Rock and another soldier stand outside the cave entrance looking to where the
Chinese might place a gun position to hit the cave. The soldier with Rock is shot
and killed by an enemy bullet. Rock and other soldiers return fire.
Rock races across the pass and up the other side and bayonets the enemy soldier.
He is furious that the men up farther did not see the enemy soldier. He
yells up: "Hey, Vogl! You guys asleep up there?" Vogl yells
back: "We didn't see nobody." Rock gets hold of Sgt. Lonergan and
beefs about Vogl and his men. After awhile Lonergan tells Rock to knock it
off. Lonergan asks if anybody has been shot? Yeah, one guy is dead.
And the one guy is the lieutenant.

Denno gets worried again. Now there are only two guys, Rock and
Lonergan, left between him and and the post of head of the platoon.
Lonergan is now platoon head. He goes around and checks on his men.
He sends a guy named Big mouth out ahead of everyone else as an early warning
system of any oncoming attack. One flare means people, two flares means
tanks. Rock has all his men in the cave bunch up so they will be warmer.

Mainotes starts to pick a fight with Denno, who threatens to box his ears.
Rock says so far they've got the Chinese fooled. They think the platoon is
the regiment. He warns the men that if they see a tank coming that means
serious business. Rock says: "A tank means they'll push through us
like we were a paper bag. So, until you hear one, take it easy."
Maniotes goes after Denno again verbally and Denno gets up and slaps the man around a bit.
Rock has the guys take off their boots and rub their feet to fight of frostbite.
Rock massages Denno's foot and then asks him how it feels? Denno says he
can't feel anything. So Rock punches Denno's foot. Still nothing.
Denno gets up to see what's going on and then everyone slowly realizes that Rock
has been massaging his own foot and has not being able to feel it. So a
peeved Rock has to get up and stomp his foot on the blanket over and over again
to get the circulation going again.
He tells everyone to hit the sack.

Denno wakes Rock up in the middle of the night to talk. The corporal
wants to know why Rock stayed in the army after World War II? Rock says he
has been wondering the why of that himself. Denno says he doesn't want to
lead because when he was in O.C.S. he got panicky on two separate occasions
where they were testing him. He sent one squad to a danger zone and one
fellow got hurt and had to have his leg amputated. In short, he says:
"I can take an order. I can't give one." He's afraid that he would
get a bunch of other soldiers killed, if he were in command. Rock tells Denno to stop worrying because he and Lonergan are going to be around for a long
time. Denno confesses now that he didn't kill that Chinese soldier that
Rock thought he had. Jonesy shot the enemy soldier.

One flare goes up. The Chinese are going around picking up their
wounded. Rock tells the men not to fire at them. He sends Denno up
to relieve Ramirez. A couple of guys fire at the Chinese. Rock has
to yell out his order again to get compliance.

The Chinese are blowing their bugles announcing an attack. But no
attack is coming. They just want to un-nerve the Americans. Whitey
says it's a psychological trick, that the Chinese are playing a traditional re-assembly tune.
Rock sends out Whitey to go get a bugle. Wolowicz volunteers to go
with Whitey. Later Whitey and his buddy Wolowicz return with a bugle.
Wolowicz, however, has been wounded. Rock gets his horn and he makes Whitey
go outside and blow it
back at the Chinese. This disturbs the Chinese who now have to run around and
see which man has lost his bugle to the enemy. They find their man
-- dead.

Rock tells Lonergan that when Whitey was out getting the bugle he didn't see
anything of Bigmouth. This hits Lonergan hard, since he sent Bigmouth out
there. So he says he's going out after him. Lonergan finds Bigmouth,
who went to sleep and now is pretty frozen. Lonergan gets Bigmouth to his
feet and they start walking back to their encampment. The two men come
under fire. Lonergan tells Bigmouth to keep going, while he fights off the
Chinese. Lonergan is hit several times by Chinese bullets. He tries
to crawl back to the encampment but he is moving through the area where the
mines have been planted.

Rock asks where's the map of the mine field? He finds out that Lonergan
has it. The doctor volunteers to go get Lonergan. The medical man
tenderly walks toward Lonergan, but steps on a mine and is killed. Now the
worried Denno agrees to go get Lonergan. He doesn't want Lonergan to die,
because that would mean that only Rock is left between Denno and being platoon
head. Denno is able to get to Lonergan. He picks the wounded man up
and carries him out of the mine area. There Lonergan is examined.
They find that the platoon leader has been too shot up and has died while being
carried by Denno.

Rock makes some fake soldiers out of the equipment once used by men now dead
and puts them around the camp. One dummy is spotted by the enemy and the
Chinese start dropping mortars on the dummy's position. This gives away
the location of the Chinese mortars and the Americans are able to knock out the
enemy mortars. Other Chinese troops start firing, but are rather quickly
killed Jonesy, however, got his left ear blown off. Rock
touches Denno's rifle barrel. It is still cold, meaning Denno did not even
fire at the Chinese. Rock forces Denno out to a position near to where
there are Chinese soldiers available to be killed. He wants Denno to kill
one of them. Denno moves out and is replaced by four of Lonergan's former
soldiers. Rock warns them about how the Chinese can so easily creep up on
soldiers and kill them. He tells the men to stay awake and stay aware of
what's going on around them.

Rock is back at the cave. He telephones the four guys at the lookout
point to ask them if they have seen anything. He says he can smell the
Reds getting closer, but they haven't seen anything. Next Rock talks to
Vogl asking if he has seen anything. They haven't seen anything.
Rock goes back to talking to Griff and the three other guys. As he is
talking to them, he asks a question and gets no response. Rock keeps
asking what's happened? The Chine communists have snuck up behind the four
Americans and killed them all. They are now setting up their guns to fire
on the American positions. The Chinese open fire and kill Vogl and all the
men with him. The Chinese mortars also inflict a lot of damage. The
firing is so intense that the soldiers have to retreat to the cave to save
themselves. .Rock tells his men that they have to hold until 9 o'clock.

Rock talks about what he would do if he were the enemy. He would fire
one bullet into the cave and the ricochet would kill everyone in there.
Another soldier says that ricochets are for the birds. Just then a Chinese
bullet enters the cave and ricochets off the walls. The Americans above
kill the lone sniper. Rock says slowly: "I was right." He has
been hit in the gun by the ricochet. Rock now tells Denno that he will be
the platoon leader. Denno says that as long as Rock is alive, he will
remain the platoon leader. Rock says slowly: "I'm dead." Denno
doesn't want to hear that and argues a bit with Rock. Rock replies:
"I told ya. I'm dead." Denno slowly lifts his head to look Rock in
the eyes. Rock is indeed dead.

One of the soldiers, Bigdeal, now tries to take command of the platoon.
He starts barking orders that they are moving out. Denno insists that they
have to stay until 9. The other fellow says he and Denno are the same
rank. Jonesy, the big American Indian, intervenes and tells off the
upstart. He says he's sticking with Denno and so is everybody else.
The upstart still insists that he is going. Finally, Denno gets up, points
his rifle at the rebel and says: "I'll clobber the first guy that tries to
bug out." The rebel now backs down and actually sits down.

As it gets close to 9, the men start preparing to move out. When
everyone is down in the pass, Denno shouts for the men to go. But as they
start marching out, they hear the sounds of a Chinese tank. The tank is
being led by one soldier who walks in front of the tank. Denno decides to
attack and destroy the tank and make a roadblock out of it. While he talks
with Whitey about it, the tank starts firing up the pass. Denno goes into
action placing the anti-tank gun and the bazookas in just the right places.
He tells the men to wait for him to fire first and then open up with everything
they've got.

The Chinese soldier is virtually directly on top of Denno, when the corporal
finally fires his weapon and kills the enemy soldier. Then the anti-tank
gun hits the tank followed by several bazooka hits. The men give a big
cheer, that is until another tank fires on them. Denno tells his men that
they will kill the soldiers with the tank and then get out of there.

At the remains of the bridge, several Americans are guarding the position.
They hear movement on the opposite shore and demand to know who goes there.
After a short moment of hesitation, the guards hear the welcome word:
"Rearguard." One of the guards fires a flare into the air. Now they
can see the remnants of the rearguard platoon slowly making their way across the
river with their wounded comrades. Denno thinks about what Rock told him
about leadership and command as he crosses the river to the other side.